Background <p>Acute undernutrition is a persistent problem in Somalia despite interventions. This is mainly due to many factors including protracted conflicts. There were numerous of pocket studies that reported different result on effect of cash transfer and nutrition outcome in Somalia. That means the current evidence remains mixed and inconclusive. The aim of this study was to systematically review available studies to understand better the effect of cash transfer on acute undernutrition in children under five and pregnant and lactating women (PLW) in Somalia.</p> Methods <p>The Preferred Reporting Items for Systematic review and Meta-Analysis (PRISMA) guidelines was employed to systematically review available studies including qualitative studies on Cash transfer and nutrition outcome among children and PLW in humanitarian settings of Somalia. Wasting (acute undernutrition) was the primary outcome of interest since humanitarian context was focused. However, stunting and underweight were also captured as secondary outcome as these indicators have limitations in humanitarian settings. No restriction except language were applied as all studies with English versions that were available in databases and non-indexed publications, such as reports and preprints, accessed via Google Scholar/Google were selected. In addition to manual searches, key phrases were searched in several databases, including PubMed/Medline, Science Direct, and Google Scholar. Two reviewers worked separately to choose, extract, and analyze data quality.</p> Result <p>A total of nine studies, seven quantitative study (Five randomized and three non-randomized) trials and two qualitative studies were included in this review. Since the study design varied, we chose not to do a meta-analysis. Quantitative studies reported mixed findings. Cash with vouchers significantly (<i>P</i> &lt; 0.05) reduce acute malnutrition in PLW in one study. Another study concluded that cash with behavioral change communication significantly (<i>P</i> &lt; 0.05) reduce acute malnutrition in children under five. This was also supported by the qualitative research findings as beneficiaries’ perception, not measured effects, suggested that cash transfers helped beneficiaries’ families and children nutrition.</p> <p>However, in the humanitarian settings of Somalia, the majority of included quantitative studies (four randomized and two non-randomized) concluded that cash alone, cash + cash, cash with voucher and cash with nutrition counselling did significantly (P &gt; 0.05) reduce acute malnutrition in children respectively.</p> Conclusion <p>Only limited evidence supports effectiveness, and that most quantitative studies did not demonstrate statistically significant reductions in acute malnutrition.</p>